Gear Oil Break-In Recommendations for New Ford PTU

[abs]

I'm doing a bunch of work on my 2010 Ford Flex Ecoboost. One of the new parts I'm installing is a brand new PTU. The new unit comes from the factory pre-filled with Motorcraft 75w-140 synthetic gear oil. This oil is known to break down and turn to a thick gloppy grease due to overheating when the PTU gear oil is not properly maintained even though Ford claims it's a "lifetime" fill. My old PTU was still functioning at 150k miles, but had quite a bit of output shaft play from wear despite fluid exchanges starting at about 60k miles. I have used the Motorcraft, Mobil 1 and Amsoil SG oils in the PTU and ultimately settled on the Mobil 1 as my top pick. So, I have a few questions for the experts here before I put any miles on this new unit:

1. What fluid should I use for break in and, does it even matter? The Motorcraft has a high dose of moly, but I will not run the Motorcraft gear oil again after the initial fill is drained.

2. How quickly should I do my first fluid exchange after I start driving on the new unit? I am thinking 5K miles might be a good target.

3. What does everyone think about dropping down to a 75w-90? For instance, I've had really good success with Mobil Delvac 75w-90 in other gear applications and it's a really stout product. As an example, my AWD 2016 Sienna uses a 75w-90 in the transfer case and I'm running the Delvac product in it without any issues. I also wonder if Ford spec'd the 75w-140 grade because a) it's the only synthetic gear oil in the Motorcraft lineup and apparently Ford is very proud of this lubricant, and b) originally the PTU was supposed to be sealed for life and they believed that the thicker fluid would not shear down to a low viscosity where damage could occur as quickly. Lastly, I would guess that the lower viscosity fluid would also run a bit cooler in the PTU?

Thanks in advance.

 

[zeng]

Quote
3. What does everyone think about dropping down to a 75w-90?

Short answer : No, and never.
Instead you should consider upgrading its KV @40C to a synthetic 80W140.

 

[dlundblad]

I would stick with Motorcraft 75w-140 personally. I would not go thinner either.

Somebody somewhere did a UOA on the fluid from one of these from an Explorer.. even with a cooler, Blackstone recommended a 5k OCI if I'm not mistaken.

Does yours have the drain plug?

 

[demarpaint]

I'd stick with the 75W-140.

 

[zrxkawboy]

I'd run the Motorcraft for a short period (maybe 5k-10k miles), then run a good quality syn in 75W140 or 80W140.

 

[umungus1122]

75w-140 synthetic and change often. They get too hot.

 

[DoubleWasp]

Given the heat, I would not go down in grade. I would definitely use a synthetic oil. Something very high grade that meets a lot of ridiculous approvals.

Since the unit does not use a lot of oil, no need to be tight about it. You already found out how quickly things can start to go downhill for a PTU. Get a superior lube and change every 5k. Hopefully you have the drain plug. If not, do one while your new one is still very accessible.

 

[JHZR2]

Definitely a good syn is needed here. I am not sure Id go with the Mobil 1; delvac 1 gear oil perhaps, or Amsoil SVG perhaps.

If for whatever reason you wanted to go lower, Id look at the 75w-110 range, but I really dont see a compelling reason why.

 

[anndel]

Drain at 10,000 miles then replace with Mobil 1 Syn Gear Lube LS 75W-140 and change every 50,000 miles. No such thing as lifetime fluids.

 

[Whimsey]

If you don't have the V-6 engine your PTU may not be exposed to the high heat that the V-6 exposes the PTU to. I have an Explorer with the 2.3 Ecoboost and luckily the exhaust is not real close to the PTU. I'm lucky mine has a drain and fill plugs plus it takes 24 oz of 75W-140, the most of any PTU's, go figure. After reading and seeing videos of black goop that was 75W-140 gear oil I had my factory fill drained and filled at 12,000 miles at the dealer. I don't know what it looked like. 10,000 miles later I had my mechanic drain and refill the PTU with Amsoil Severe Gear 75W-140. The replacement Motorcraft 75W-140 that came from the dealer's d & f came out like it went in, flowed easily and was a golden color, it looked good at 10,000 miles. If you have the V-6 and I believe your unit only holds ~13 oz, I'd do an initial drain at 10,000 miles and see what the Motorcraft 75W-140 looks like. If it looks ok you can go longer next time, 15,-20,000 mi. As far as fluids I'm using Amsoil Severe Gear 75W-140 because I feel it's more stout than the Motorcraft. I'm sure Mobil 1 or Redline synthetic gear oils would be good as well in the 15,000-20,000 mile range.

Whimsey

 

[4WD]

Always noticed M1 in the 140 was a fair amount more than the M1 90. Someone (Overkill?) posted the SDS on M1 140 ... it was PAO ...

 

[threeputtpar]

My experience is from a 2008 Taurus X. Got the vehicle at 118k miles with no service ever on the PTU. Had to extract the sludge from the top vent hole where the pressure was pushing it out.

Early ones didn't have the drain plug, so I drilled and tapped on in myself. Couldn't get the lowest point due to gears close to the case, but it drained about 13 of the 18 ounce capacity. I ran 3 5k mile intervals with Walmart 75W-140 and then filled with Shaeffer's 75W-140 lube made for motorcycle gear cases. Probably the best 75W-140 you can get for the application.

 

[Dino01]

From what I've read about PTU issues, they may be one instance when expensive boutique oils are warranted. I'd go 75w140 Amsoil or Redline if it were mine. For reference I'm all about manufacturers specs andOE fluids but the PTUs seem hard on fluid so something a little fancier may help here

 

[DoubleWasp]

Anything truly operating at-the-limit is exactly what boutique oils were made for. It's where they shine and get real friendly on the wallet.

Major factor here is the volume of fluid. It's low. This limits the expenditure by a large margin.

 

[edyvw]

I would join others in recommending boutique oils or if you can find Castrol Syntrax 75W140 that is not limited slip since that goes into applications like Mercedes AMG, BMW M etc.
Also, since you have Sienna, question for you: what do you run in transmission? I am about to do transmission and transfer case fluid change in 10k in my AWD Sienna.

 

[metroplex]

The hottest part of the PTU gets to about 287F on the casing.
I recall someone here saying that 75W-140 will start to break down fast above 250F. I'm assuming that if the casing gets to 287F, then the oil is actually much hotter?
Would it be advisable to just go with an even thicker gear oil than 75W-140?

What about using Amsoil SAE 190 or SAE 250?

https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-sae-190/?code=SRNQT-EA

https://www.amsoil.com/shop/by-product/gear-lube/severe-gear-sae-250/?code=SRTQT-EA

Would these be too thick for the PTU?

 

[zeng]

IMHO, any 75W140 is a no go in this application never mind what the OEM/oil marketer says.